The present invention relates to a method and apparatus for automatically processing a patient""s biological fluids such as urine, blood serum, plasma, cerebrospinal fluid and the like. In particular, the present invention provides a stackable vessel for containing a plurality of liquid aliquot portions of patient samples in individual test wells.
Various types of tests related to patient diagnosis and therapy can be performed by analysis assays of a sample of a patient""s infections, bodily fluids or abscesses for an analyte of interest. Such patient samples are typically liquids placed in sample vials, are extracted from the vials, combined with various reagents in special reaction vessels or tubes, incubated, and analyzed to aid in treatment of the patient. In a typical clinical chemical analysis, one or two assay reagents are added at separate times to a liquid sample having a known concentration, the sample-reagent combination is mixed and incubated. Interrogating measurements, turbidimetric or fluorometric or absorption readings or the like, are made to ascertain end-point or rate values from which an amount of analyte may be determined, using well-known calibration techniques.
Although various known clinical analyzers for chemical, immunochemical and biological testing of samples are available, analytical clinical technology is challenged by increasing needs for improved levels of analysis. Automated clinical analyzers improve operating efficiency by providing results more rapidly while minimizing operator or technician error. However, due to increasing demands on clinical laboratories regarding assay throughput, new assays for additional analytes, accuracy of analytical results, and low reagent consumption, there continues to be a need for improvements in the overall performance of automated clinical analyzers. In particular, the efficiency of patient sample handling continually needs to be increased, regardless of the assay to be performed.
An important contributor to maintaining a high efficiency in throughput of patient samples is the ability to quickly and securely introduce a plurality of samples to the sample testing portion of an analyzer. Patient samples are typically held in a container such as a sample cup, a primary tube, or any other suitable container and may be open at its top or closed with a stopper or lid or the like at its top. To increase handling efficiency, the containers may then be placed into a sample rack adapted to support multiple sample containers generally in an upright orientation.
The sample rack is usually placed by an operator in an input portion of the analyzer and then moved automatically moved by the analyzer to a location where a portion of the liquid patient sample, hereinafter described as a aliquot, is extracted, usually by aspiration using a hollow, needle like probe from the sample container for testing in the analyzer. Afterwards, the aliquot may be dispensed directly into a sample test vessel or into an interim aliquot vessel prior to a later transfer into a sample test vessel.
In analyzers designed for high assay throughput numbers, efficiently handling a large number of samples introduces a number of special challenges due to simultaneous desires to maintain a relatively small analyzer footprint, maintain sample aliquots on-board the analyzer for potential re-testings, eliminate concerns for cross-contamination when reusing sample vessels, while at the same time minimizing costs associated with disposable sample vessels, etc.
It is therefore desirable to provide an aliquot vessel of small physical size, of low cost and with features permitting it to be reliably handled by automated devices. It is particularly desirable that such an aliquot vessel be able to be transported in a one-dimension linear plane on-board an analyzer so as to eliminate the necessity and expense of two-directional handling means. It is further desirable that such an aliquot vessel be capable of easily being loaded by an operator onto an analyzer, ideally being loaded from multiple vessel put-ups. It is even further desirable that such an aliquot vessel comprise a plurality of individual aliquot wells so that a single aliquot vessel accommodate a large number of different samples, for example in an array of aliquot vessels.
U.S. Pat. No. 6,190,617 provides for a test sample container including an upper skirt and a body having a reservoir for receipt of the test sample. The segment includes a base, a frame, and a handle. The frame has a shelf for which the upper skirt of the test sample container rests on, and has openings for receipt of the body of the sample container. The carousel has a carousel trough for receipt of the base of the sample container segment, and has a plurality of alignment pins disposed in the carousel trough. The base of the sample container segment has a circular slot and an elongated slot for receiving the alignment pins and positioning the sample container segment relative to the carousel.
The present invention provides a aliquot vessel array adapted with a plurality of individual sample aliquot wells and capable of being attached one atop another in a secure stack. The sample aliquot wells are designed to minimize so-called xe2x80x9cdead sample volumexe2x80x9d inaccessible by typical aspiration means. A number of stacked aliquot vessel arrays may be simultaneously loaded by an operator into a elevator-like storage unit on an analyzer and dispensed in a singulated stream onto a sampling track as required by the analyzer. Handling features are designed into the aliquot vessel array to ensure safe and reliable movement between the storage unit and linear sampling tracks where sample is originally dispensed into individual wells and later aspirated therefrom for sample liquid analysis. The aliquot vessel array is typically covered with an evaporation and protection layer and further includes alignment features so that multiple aspirations may be made from single punctures through the protection layer.